1. Field of the Invention
The present invention relates to an observation method for observing a biological tissue in a living state (in vivo).
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2006-105591, filed on Apr. 6, 2006, and Japanese Patent Application No. 2007-74971, filed on Mar. 22, 2007, the entire contents of these applications are incorporated herein by reference.
2. Description of Related Art
Conventionally, as this kind of observation method, for example, an observation method disclosed in Japanese Unexamined Patent Application, Publication No. 2005-253836, is known.
In this observation method, an objective optical unit which stores an objective optical system in an outer sheath is supported in a hole formed in a biological tissue in an inserted state by a supporting member, to fix the supporting member to the biological tissue, and thereby the same observation target site in the marrow can be observed with a high reproducibility by inserting and withdrawing the objective optical unit through the supporting member.
However, in the observation method disclosed in Japanese Unexamined Patent Application, Publication No. 2005-253836, no case is disclosed where an observation target which is within an internal area defined by a membranous tissue or the like filled with a body fluid is observed.
That is, for example, the inside of the amniotic membrane is filled with the amniotic fluid, and if a fetus exists inside thereof, the objective optical unit has to be inserted through the amniotic membrane. Moreover, after a through hole is formed in the amniotic membrane and the observation is completed, and after the objective optical unit is withdrawn, the amniotic fluid has to be continuously held in the amniotic membrane.
However, if the amniotic membrane simply passes through by the distal end of the objective optical unit, there is a disadvantage in that the internal amniotic fluid leaks out due to the internal pressure inside the amniotic membrane, and the observation target such as the fetus floating in the amniotic fluid in a healthy state can not be observed. Moreover, there is a disadvantage in that, after a through hole is formed in the amniotic membrane and the observation is completed, when the objective optical unit is withdrawn, the internal amniotic fluid leaks out due to the internal pressure inside the amniotic membrane, and thereby the amniotic fluid can not be continuously held in the amniotic membrane.